In the field of automatic fastener insert mechanisms it is generally necessary to provide some kind of escapement, transfer, or feed mechanism whereby fasteners may be picked off a track or line of fasteners being continuously supplied thereto and transferred, one at a time, to a flexible conduit through which they are delivered to the fastener inserting mechanism for emplacement into the work piece. One such mechanism is illustrated and described in U.S. Pat. No. 3,946,926, in which the escapement mechanism includes a slide which receives the fasteners and moves one fastener laterally to a position over the flexible conduit. The slide is operated by a solenoid. When the fastener is moved to the position over the flexible conduit it drops by a combination of gravity and vacuum from a fluid pressure source introduced downstream of the outlet, from whence the fasteners are directed to the emplacement mechanism. In a second embodiment similar to the first, the solenoid is replaced by an air cylinder in which the plunger thereof operates the slide but is basically the same as the solenoid operated slide approach.
In a third type of embodiment illustrated and described in U.S. Pat. No. 3,906,615, the slide may be operated by either the solenoid or plunger of the air cylinder described hereinabove. However, the air which conveys the fastener from the outlet of the escapement mechanism to the emplacement mechanism flows vertically from above the outlet if it is at the bottom, or below the outlet if it is at the top, through that portion of the escapement mechanism and pushes the fastener in the desired direction.
In either of the devices described hereinabove there are two activation systems necessary, one to move the slide from its receiving position to the delivery position and a second for actually moving the fastener through the flexible conduit. The second system is activated when the first has completed its operation. This leads to several disadvantages which have been noticed. First of all, there is extra, unnecessary equipment required for the two activating systems. With the additional equipment there is a greater chance of malfunction. Because of the two activating systems, the second system relies on the first activating system to get the fastener to the proper evacuation position and to get it there at the proper time. Timing of the second system with relation to the first then becomes very important.